The anterior segment of the eye in diabetes

Diabetes more than retinopathy, it’s effect on the anterior segment of eye

Diabetes mellitus (DM) is one of the chronic metabolic noncommunicable diseases that has attained worldwide epidemics. It threatens healthy life around the globe, with mild-to-severe secondary complications and leads to significant illness including nephropathy, neuropathy, retinopathy, and macrovascular abnormalities including peripheral vasculopathy, and ischaemic heart disease. Research into diabetic retinopathy (DR), which affects one-third of persons with diabetes, has made considerable strides in recent years. In addition, it can lead to several anterior segment complications such as glaucoma, cataract, cornea, conjunctiva, lacrimal glands and other ocular surface diseases. Uncontrolled DM also caused gradual damage to corneal nerves and epithelial cells, which raises the likelihood of anterior segment diseases including corneal ulcers, dry eye disease, and chronic epithelial abnormalities. Although DR and other associated ocular complications are well-known, the complexity of its aetiology and diagnosis makes therapeutic intervention challenging. Strict glycaemic control, early detection and regular screening, and meticulous management is the key to halting the progression of the disease. In this review manuscript, we aim to provide an in-depth understanding of the broad spectrum of diabetic complications in the anterior segment of the ocular tissues and illustrate the progression of diabetes and its pathophysiology, epidemiology, and prospective therapeutic targets. This first such review article will highlight the role of diagnosing and treating patients with a plethora of anterior segment diseases associated with diabetes, which are often neglected.

Diabetic eye: associated diseases, drugs in clinic, and role of self-assembled carriers in topical treatment

Introduction: Diabetes is a pandemic disease that causes relevant ocular pathologies. Diabetic retinopathy, macular edema, cataracts, glaucoma, or keratopathy strongly impact the quality of life of the patients. In addition to glycemic control, intense research is devoted to finding more efficient ocular drugs and improved delivery systems that can overcome eye barriers. Areas covered: The aim of this review is to revisit first the role of diabetes in the development of chronic eye diseases. Then, commercially available drugs and new candidates in clinical trials are tackled together with the pros and cons of their administration routes. Subsequent sections deal with self-assembled drug carriers suitable for eye instillation combining patient-friendly administration with high ocular bioavailability. Performance of topically administered polymeric micelles, liposomes, and niosomes for the management of diabetic eye diseases is analyzed in the light of ex vivo and in vivo results and outcomes of clinical trials. Expert opinion: Self-assembled carriers are being shown useful for efficient delivery of not only a variety of small drugs but also macromolecules (e.g. antibodies) and genes. Successful design of drug carriers may offer alternatives to intraocular injections and improve the treatment of both anterior and posterior segments diabetic eye diseases.

Scheimpflug Camera and Swept-Source Optical Coherence Tomography in Pachymetry Evaluation of Diabetic Patients

Aim

The comparative analysis of the central and peripheral corneal thicknesses using two different imaging systems: Scheimpflug camera and swept-source OCT was performed to investigate the differences in corneal thickness analysis in diabetic patients.

Materials and Methods

The study group consisted of the 147 eyes of 107 diabetic patients who were examined and compared with 138 eyes of 89 nondiabetic cataract patients. The inclusion criteria for the study group was diabetes mellitus type II identified no less than 10 years ago, with NPDR not requiring prior laser treatment. The control group was recruited from nondiabetic patients. Measurements were obtained on the Pentacam Scheimpflug imaging system and Casia swept-source OCT. All study parameters from anterior chamber images were processed for five different zones, the central zone and four peripherals—superior, inferior, nasal, and temporal. A fit zone diameter of 4 mm was applied for both instruments.

Results

The Pentacam system overestimated corneal measurements in the DM group when compared with the Casia OCT in superior corneal zone (p=0.04), inferior corneal zone (p=0.02), nasal corneal zone (p < 0.001), and temporal corneal zone (p=0.01). In the control group, there were also statistically significant differences between the Pentacam and Casia OCT measured values in inferior corneal zone (p=0.001), nasal corneal zone (p=0.04), and temporal corneal zone (p < 0.001).

Conclusion

Scheimpflug camera pachymetry measurements showed statistically higher CCT values when compared with swept-source OCT measurements.

Phacoemulsification without preoperative mydriasis in patients with age-related cataract associated with type 2 diabetes

Aim

To study the effect of intracameral injection of preservative-free lignocaine to induce pupil dilatation, without using any preoperative dilating eyedrops or intraoperative mydriatics in patients with age-related cataract associated with type 2 diabetes mellitus.

Design

This was a prospective, observational, and interventional case series conducted at a tertiary eyecare center in rural India.

Materials and methods

A total of 32 patients underwent phacoemulsification under topical anesthesia for visually significant cataract. Preoperative pupillary diameter was measured 3 days prior to surgical procedure under mydriatics (tropicamide 0.8%, phenylephrine hydrochloride 5%). Intraoperative pupillary dilatation was achieved by 1% intracameral lignocaine solution alone. Effective phacoemulsification time (EPT), total surgical time, and final pupillary diameter were recorded at the conclusion of surgery.

Results

The average duration of diabetes was 11.2 (range 5–25) years. There was no difference in dilatation by preoperative pupil-dilating drops (5.2±0.5 mm, range 3–8.3 mm) and intracameral 1% lignocaine during the surgical procedure (P=0.63). There was a negative correlation (r=−0.92) between diabetes duration and dilatation of pupils with dilating drops and intracameral lignocaine. The duration of the surgery, EPT, and phacoemulsification chop had statistically insignificant effects on mydriasis, while the grade of the nucleus had a statistically significant effect on mydriasis. Intracameral lignocaine had no significant effect on blood pressure or pulse. There were no surgical complications that could have compromised the visual outcome. None of the patients developed macular edema in a follow-up period of 3 months; 28 patients (87.5%) had best-corrected visual acuity from 20/30 to 20/20.

Conclusion

Intracameral lignocaine 1% provides sufficient mydriasis for the safe phacoemulsification of cataract in patients with type 2 diabetes of variable duration.

Prophylactic postoperative ketorolac improves outcomes in diabetic patients assigned for cataract surgery

Objective

To evaluate the prophylactic role of topical non-steroidal anti-inflammatory drugs in reducing the incidence of central macular edema (CME) in diabetic eyes post-cataract surgery.

Patients and methods

This study included 86 eyes (70 patients) with high risk characteristics for the development of CME after cataract surgery. All patients underwent phacoemulsification and intraocular lens implantation. Patients were divided into two equal groups (n = 43 [eyes]): a control group given topical dexamethasone 0.1%, four times/day for 12 weeks postoperatively and a study group given topical ketorolac tromethamine 0.4% twice daily in addition to topical dexamethasone 0.1% four times daily for 12 weeks. Patients were examined at 3, 6, and 12 weeks postoperatively for evaluation of CME development. The main study outcome was the change in the retinal fovea thickness measured with ocular coherence topography.

Results

Ten eyes developed CME (11.6%); eight eyes in the control group and only two eyes in the study group. Mean retinal fovea thickness was significantly higher in the control group compared to the study group. Moreover, eyes of the control group developed CME significantly earlier than those of the study group.

Conclusion

Prophylactic postoperative ketorolac 0.4% may have a role in reducing the frequency and severity of CME in diabetic eyes post-cataract surgery.